The purpose of this project is to develop and evaluate a method for quantitative measurement of bloodflow in gingival tissues. A new non-invasive optical method for measuring bloodflow; Laser Doppler Velocimetry (LDV) has been developed by NHLBI. This method has been modified and adapted for intra-oral use by fabricating special probes which reproducibly position the fiber optic source-detector system in the mouth. Preliminary results indicate that the system can reliably detect changes in gingival blood flow induced by pressure occlusion and vascoconstricting drugs.